Main windows – PB Docs 2019

Main windows are standalone windows that are independent of all
other windows. They can overlap other windows and can be overlapped by
other windows.

You use a main window as the anchor for your application. The
first window your application opens is a main window unless you are
building a Multiple Document Interface (MDI) application, in which
case the first window is an MDI frame.

For more on building MDI applications, see the section called “Building an MDI Application” in Application Techniques.

Using main windows

Define your independent windows as main windows. For example,
assume that your application contains a calculator or scratch pad
window that you want to have always available to the user. Make it a
main window, which can be displayed at any time anywhere on the
screen. As a main window, it can overlap other windows on the
screen.